Caveolin-1 is an integral protein of caveolae, known to play important roles in signal transduction and lipid transport. We have documented that caveolin-1 (cav-1) expression is increased in metastatic prostate cancer and is also increased in primary and metastatic human prostate cancer following androgen ablation therapy. We have also shown that the level of cav-1 expression in radical prostatectomy specimens is predictive of recurrence and is higher in African-American men. Recently, we have shown that cav-1 is secreted by androgen-insensitive prostate cancer cells and have developed an indirect sandwich ELISA to measure the level of cav-1 in serum. We propose to exploit the expression and selective secretion of cav-1 by aggressive prostate cancer cells toward the development of novel prognostic tests for prostate cancer progression. Initially we will correlate tissue (needle biopsy and radical prostatectomy specimens) and serum cav-1 in a panel of prostate cancer patients and controls to determine the sensitivity and specificity of our assays. We will further conduct a retrospective cohort study to assess the predictive value of pre-operative tissue and serum cav-1 levels in regard to pathologic features of the cancer and biochemical (serum PSA) recurrence. We will also conduct a prospective population-based study involving men enrolled in the BCM SPORE who have been diagnosed with prostate cancer and who will undergo a radical prostatectomy at our institution. This study will provide important information regarding the capacity of tissue and/or serum cav-1 levels to identify aggressive disease prior to treatment. Finally we will conduct a retrospective study that will assess the value of serum cav-1 levels as a risk factor for the development of prostate cancer. This study will be an ancillary study to the therosclerosis Risk in Communities (ARIC) study cohort.